Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties

First published online: 26 Feb 2016Upconversion photoluminescence is a nonlinear effect where multiple lower energy excitation photons produce higher energy emission photons. This fundamentally interesting process has many applications in biomedical imaging, light source and display technology, and solar energy harvesting. In this review we discuss the underlying physical principles and their modelling using rate equations. We discuss how the understanding of photophysical processes enabled a strategic influence over the optical properties of upconversion especially in rationally designed materials. We subsequently present an overview of recent experimental strategies to control and optimize the optical properties of upconversion nanoparticles, focussing on their emission spectral properties and brightness.Annemarie Nadort, Jiangbo Zhao and Ewa M. Goldy

Sensitive cytokine assay based on optical fiber allowing localized and spatially resolved detection of interleukin-6

We demonstrated a cytokine detection device based on gold nanoparticle modified silica optical fiber for the monitoring of locally variable cytokine interleukin-6 (IL-6) concentrations using a sandwich immunoassay scheme. The fiber is designed to be introduced into an intrathecal catheter with micrometer-sized holes drilled along its length to enable fluid exchange between the outside and inside of the catheter. An exposed optical fiber (diameter 125 μm) modified with a layer of gold nanoparticles was functionalized with the IL-6 capture antibody to form the sensing interface. The immunocapture device was incubated with a cytokine solution to capture the analyte. The device was then exposed to the IL-6 detection antibody which was loaded on the fluorescently labeled magnetic nanoparticles, making it possible to quantify the cytokine concentration based on the intensity of fluorescence. A reliable method for quantifying the fluorescent signal on a 3D structure was developed. This device was applied to the detection of cytokine IL-6 with the low limit of detection of 1 pg mL⁻¹ in a sample volume of 1 μL. The device has the linear detection range of 1–400 pg mL⁻¹ and spatial resolution on the order of 200–450 μm, and it is capable of detecting localized IL-6 secreted by live BV2 cells following their liposaccharide stimulation. This biological detection system is suitable for monitoring multiple health conditions.Guozhen Liu, Kaixin Zhang, Annemarie Nadort, Mark R. Hutchinson, and Ewa M. Goldy

Background free imaging of upconversion nanoparticle distribution in human skin

Widespread applications of nanotechnology materials have raised safety concerns due to their possible penetration through skin and concomitant uptake in the organism. This calls for systematic study of nanoparticle transport kinetics in skin, where high-resolution optical imaging approaches are often preferred. We report on application of emerging luminescence nanomaterial, called upconversion nanoparticles (UCNPs), to optical imaging in skin that results in complete suppression of background due to the excitation light back-scattering and biological tissue autofluorescence. Freshly excised intact and microneedle-treated human skin samples were topically coated with oil formulation of UCNPs and optically imaged. In the first case, 8- and 32-nm UCNPs stayed at the topmost layer of the intact skin, stratum corneum. In the second case, 8-nm nanoparticles were found localized at indentations made by the microneedle spreading in dermis very slowly (estimated diffusion coefficient, D-np = 3-7 x 10(-12) cm(2) . s(-1)). The maximum possible UCNP-imaging contrast was attained by suppressing the background level to that of the electronic noise, which was estimated to be superior in comparison with the existing optical labels. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)

Association between lipophilic beta-blockers and depression in diabetic patients on chronic dialysis

BACKGROUND: Depression is associated with lower quality of life and increased risk of mortality. The prevalence of depression in chronic dialysis patients. as well as in patients with diabetes, is more than 20%. It is debated whether use of beta-blockers increases the risk of depression. Therefore. we examined in chronic dialysis patients with and without diabetes. the association between beta-blockers and depressive symptoms.METHODS: Data were collected from the DIVERS-I study. a multicentre prospective cohort among chronic dialysis patients in the Netherlands Depressive symptoms were assessed with the Beck Depression Inventory (BDI-II). We defined depressive symptoms as a BDI-II score >= 16. The cross-sectional association at baseline between depressive symptoms and beta-blocker use in chronic dialysis patients. was studied by multivariable logistic regression adjusted for potential confounders.RESULTS: We included 684 chronic dialysis patients, of whom 43% had diabetes mellitus, and 57% used a beta-blocker of which 97% were lipophilic. After multivariable adjustment, the OR (95% CI) for depressive symptoms in patients with compared to without diabetes was 1.41 (1.00-1.98), and in beta-blocker users compared to non-users 1.12 (0.80-1.56), respectively. Dialysis patients with diabetes and beta-blocker use compared to those without diabetes and not using beta-blockers had an OR of 1.73 (1.12-2.69) for depressive symptoms. The association was stronger in dialysis patients with diabetes and lipophilic beta-blocker use with an OR of 1.77 (1.14-2.74).CONCLUSIONS: We found a possible association between lipophilic beta-blocker use and depressive symptoms in chronic dialysis patients with diabetes.Clinical epidemiolog

Implementation of outpatient schema therapy for borderline personality disorder: study design

ABSTRACT: BACKGROUND: Schema Therapy (ST) is an integrative psychotherapy based upon a cognitive schema model which aims at identifying and changing dysfunctional schemas and modes through cognitive, experiential and behavioral pathways. It is specifically developed for patients with personality disorders. Its effectiveness and efficiency have been demonstrated in a few randomized controlled trials, but ST has not been evaluated in regular mental healthcare settings. This paper describes the study protocol of a multisite randomized 2-group design, aimed at evaluating the implementation of outpatient schema therapy for patients with borderline personality disorder (BPD) in regular mental healthcare and at determining the added value of therapist telephone availability outside office hours in case of crisis. METHODS/DESIGN: Patient outcome measures will be assessed with a semi-structured interview and self-report measures on BPD, therapeutic alliance, quality of life, costs and general psychopathology at baseline, 6, 12, 18 and 36 months. Intention-to-treat analyses will be executed with survival analysis for dichotomous variables, and one-sample t-tests and ANCOVAs for continuous variables with baseline as covariate and condition as between group factor. All tests will be two-tailed with a significance level of 5%. DISCUSSION: The study will provide an answer to the question whether ST can be effectively implemented and whether phone support by the therapist has an additional value. TRIAL REGISTRATION: The Dutch Cochrane Center, NTR (TC = 1781

Association between benzodiazepine use and exacerbations and mortality in patients with asthma: a matched case-control and survival analysis using the United Kingdom Clinical Practice Research Datalink

Purpose: To investigate the association between the GABAergic drugs, benzodiazepines or zopiclone, and the occurrence of asthma exacerbations and subsequent mortality in a cohort of asthma patients. Methods: 105,747 patients without asthma exacerbation and 25,895 patients with exacerbated asthma were included. A nested case-control study probed the association between benzodiazepines or zopiclone and occurrence of asthma exacerbation (primary outcome) using conditional logistic regression. Cox regression was used to determine the association between the drugs and all-cause mortality in patients with recorded asthma exacerbation. Adjusted matched odds ratios (adj mOR), and adjusted hazard ratios (adj HR) with 95% confidence intervals (CI) are presented. Results: Current benzodiazepine use was associated with increased occurrence of asthma exacerbation (adj mOR 1.49; 1.15-1.93; P=0.001) as was current zopiclone use (adj mOR 1.59; 95% CI 1.37-1.85; P<0.001). In patients with an asthma exacerbation, current benzodiazepine use was associated with increased all-cause mortality during a median follow-up of 2 years (adj HR 2.78; 95% CI 1.26-6.12; P=0.011), and the association between zopiclone use and all-cause mortality showed borderline statistical significance (adj HR 1.58; 95% CI 0.98-2.54; P=0.058). Conclusion: Benzodiazepines and zopiclone may increase the likelihood of asthma exacerbation and benzodiazepines may also increase the likelihood of mortality following exacerbation. These data suggest that caution should be exercised when prescribing benzodiazepines to patients with asthma

Schema therapy for emotional dysregulation: Theoretical implication and clinical applications

The term emotional dysregulation refers to an impaired ability to regulate unwanted emotional states. Scientific evidence supports the idea that emotional dysregulation underlies several psychological disorders as, for example: personality disorders, bipolar disorder type II, interpersonal trauma, anxiety disorders, mood disorders and posttraumatic stress disorder. Emotional dysregulation may derive from early interpersonal traumas in childhood. These early traumatic events create a persistent sensitization of the central nervous system in relation to early life stressing events. For this reason, some authors suggest a common endophenotypical origin across psychopathologies. In the last 20 years, cognitive behavioral therapy has increasingly adopted an interactiveontogenetic view to explain the development of disorders associated to emotional dysregulation. Unfortunately, standard Cognitive Behavior Therapy (CBT) methods are not useful in treating emotional dysregulation. A CBT-derived new approach called Schema Therapy (ST), that integrates theory and techniques from psychodynamic and emotion focused therapy, holds the promise to fill this gap in cognitive literature. In this model, psychopathology is viewed as the interaction between the innate temperament of the child and the early experiences of deprivation or frustration of the subject\u2019s basic needs. This deprivation may lead to develop early maladaptive schemas (EMS), and maladaptive Modes. In the present paper we point out that EMSs and Modes are associated with either dysregulated emotions or with dysregulatory strategies that produce and maintain problematic emotional responses. Thanks to a special focus on the therapeutic relationship and emotion focused-experiential techniques, this approach successfully treats severe emotional dysregulation. In this paper, we make several comparisons between the main ideas of ST and the science of emotion regulation, and we present how to conceptualize pathological phenomena in terms of failed regulation and some of the ST strategies and techniques to foster successful regulation in patients